This article will explain how campaigns, and experiences, work with one another.
By default, a visitor can be bucketed into multiple campaigns, if they match the criteria of them all. If they match multiple campaigns on the same page, all of them will fire simultaneously
However, this can be changed in Campaign Settings. You have the option to either allow or not allow simultaneous campaigns.
Within both these options, you are able to create exclusion groups.
For example, if you have 'Allow Simultaneous Campaigns' set to 'Yes', then all campaigns will fire together. However, any selected in the exclusion group would not be able to fire together, and instead the first campaign to match would fire.
You are able to specify if this exclusion should be page, session or journey based.